Induction of labor

Post-induction vs. spontaneous onset of labor

I'm at the end of my pregnancy and my doctor is suggesting induction.

Is it always better to go into labor spontaneously?

Does induction have a higher rate of cesarean sections than spontaneous onset of labor?

Dear expectant mother,

We know that induction of labor can raise many questions and concerns. We want you to feel safe and calm because we will respect your decisions, your well-being, and that of your baby at all times. Our goal is to accompany you through this process with the utmost respect and care.

1. Information and autonomy: you decide
   • Before starting the induction, we will explain in detail the medical reasons, the available methods, and what you can expect at each step.
   • You will have the opportunity to ask any questions you need and express your wishes or concerns.
   • We respect your autonomy: the final decision will always be yours.
2. Induction Methods: Prioritizing Safety and Comfort
   • There are different methods to induce labor, such as prostaglandins (misoprostol or dinoprostone), oxytocin, or mechanical methods. We will choose the most appropriate method for you and your baby, always with your informed consent.
   • If at any time you wish to pause or reconsider the procedure, we will be there to listen and support you.
3. A Calm and Supportive Environment
   • You can be accompanied by the person of your choice during the process, because your emotional well-being is just as important as your physical well-being.
   • We will create a respectful environment where you feel safe, comfortable, and in control of the situation.
4. Listen to Your Body: Every Process Is Unique
   • Every woman and every baby have their own rhythm. We will respect your body's time to respond to induction and make decisions based on how you feel and how labor progresses.
   • If you experience discomfort at any time, we will offer you different options to relieve it, including relaxation techniques, position changes, and, if desired, pain relief.
5. Open and ongoing communication
   • You will be informed of the progress of the process at all times and will be able to express how you feel.
   • We will respect your decisions about your mobility, your preferred delivery method, and any other preferences you may have within a safe environment.

Our commitment is that you experience this moment with confidence, respect, and the best possible care. We will be by your side, accompanying you with professionalism and warmth, ensuring that both you and your baby are in the best hands.

If you have questions or need more information, we are here to listen.

💙 We are with you on this beautiful journey toward the birth of your baby.

Here are some more specific explanations, addressed from a more technical perspective, that we hope will be of interest to you and help resolve any doubts.

The 2011 WHO guidelines on induction of labour are summarised in the following table:

To implement these recommendations, evidence was sought from a Cochrane systematic review of 22 randomized controlled trials. The trials evaluated the effect of labor induction at 37–40 weeks, 41 completed weeks, and 42 completed weeks of gestation, and the intervention was compared with expectant management with fetal monitoring at variable intervals. There were no statistical or clinical differences in the comparisons and outcomes, except for a reduction in perinatal deaths when labor was induced at 41 completed weeks. The resulting relative risk (RR) was 0.27, with a 95% confidence interval (CI) of 0.08–0.98. This increased relative risk implies 2.18 additional fetal deaths per 1000 pregnancies of more than 41 weeks in the expectant management group compared to the induction group.

Recommendations

• Induction of labor is recommended for women whose gestational age is known with certainty and who have reached 41 weeks (> 40 weeks + 7 days) of gestation. (Low-quality evidence. Weak recommendation.)
• Induction of labor is not recommended for women with an uncomplicated pregnancy before 41 weeks of gestation. (Low-quality evidence. Weak recommendation.)

Remarks

• Recommendation 1 does not apply in settings where gestational age cannot be reliably estimated.
• There is insufficient evidence to recommend induction of labor for uncomplicated pregnancies before 41 weeks of gestation.

But what about special situations? For example, suspected macrosomia:

Recommendation for suspected macrosomia

To obtain evidence on this indication, the guideline development group updated the existing systematic review (12), which included three trials, incorporating data from a recent unpublished trial evaluating induction of labor for suspected macrosomia.

In priority comparisons and outcomes, induction of labor at term was similar to expectant management. Regarding other outcomes relevant to this comparison, but not prioritized for these guidelines, induction of labor was associated with a lower incidence of clavicle and arm fractures due to shoulder dystocia (four trials, 1189 participants, RR 0.2, 95% CI 0.05–0.79) (Table EB 1.3.1).

Recommendation 

1. Induction of labor at term for suspected macrosomia is not recommended. (Low-quality evidence. Weak recommendation.)

Observation

1. Confirmation of suspected macrosomia relies on reliable determination of fetal age and weight, which requires ultrasound assessments early in pregnancy and again near term. Because ultrasound may not be available or accessible to all women in resource-limited settings, participants in the technical consultation preferred not to recommend induction of labor for suspected macrosomia, although they acknowledged that, in cases of confirmed macrosomia, induction of labor could reduce the incidence of clavicle fracture due to shoulder dystocia. (That is, induction is preferred not to recommend induction, not because it has not been shown to reduce complications, but because there are many settings around the world where ultrasound cannot be performed.)

WHO Recommendation for Premature Rupture of Membranes:

Recommendation:

1. Induction of labor is recommended for women with premature rupture of membranes at term.(High-quality evidence. Strong recommendation.)

Observation:

1. Participants in the WHO technical consultation noted that, in the trials included in the Cochrane review, induction of labor had been initiated within 24 hours of rupture of membranes. They also emphasized that oxytocin should be considered the first option for induction of labor in women with premature rupture of membranes.

In 2018, a prospective, randomized, randomized study was published in the NEJM, one of the most prestigious and impactful scientific journals in the world. This is the type of study that provides the highest quality of scientific evidence available to answer the question:

Is induction at term better or waiting for spontaneous labor to begin?

In this study, 6,106 at-risk primiparous women were randomized and seen at week 38, 3062 were assigned to the induced labor group and 3044 to the expectant management group. The results are statistically significant and show the following:

• Fewer perinatal complications in the induction group (4.3% vs. 5.4% in the expectant management group), as well as shorter duration of respiratory support and length of hospital stay.
• A lower percentage of cesarean sections in the induction group (18% vs. 22.2%). One cesarean section is avoided every 28 births in nulliparous women who are induced at 39 weeks of labor.
• Lower percentage of hypertension associated with pregnancy in the induction group.
• Fewer complications in the case of cesarean section in the induction group.
• Women in the induction group reported less pain and lower Likert scale scores.
• Women in the induction group perceived greater control over labor.
• Women in the induction group spent more time in the delivery room, but less total hospitalization.

To date, several observational studies have described that induction of labor is associated with a higher risk of maternal and neonatal adverse effects. However, in this prospective, randomized study, no significant differences were observed in the frequency of adverse perinatal outcomes, and the differences observed were in favor of induction.

The relative risk of neonatal complications is 20% lower in the induction group. This conclusion is consistent with other observational studies and another randomized study (the only one other than the one mentioned above), that of Walker&Cols.

However, as the article by Grobman&Cols. points out, these studies retrospectively compare women who had spontaneous labor with women who had induced labor, which is not exactly the comparison we need to answer the question. It is better to compare: women at term, some who are induced vs. others who are maintained on expectant management.

What does an induction of labor entail?

At our center, patients are admitted to begin induction. First, a medical history is taken, the mother and fetus are monitored for 20-30 minutes, and then, depending on the conditions and the mother's wishes, a method aimed at ripening the cervix or a method aimed at achieving contractions can be chosen.

• Cervical ripening is the procedure aimed at facilitating the softening, effacement, and dilation of the cervix.
• Labor induction is the procedure aimed at triggering uterine contractions to achieve vaginal delivery.

Cervical ripening:

When we talk about the condition of the cervix, we refer to whether the cervix is more or less shortened or more or less open. This is what we call the Bishop index:

One of the methods that can be used for cervical ripening is the administration of prostaglandins vaginally.

When the patient is admitted, a fetal monitor is first used for 20-30 minutes, and if everything is okay, the medication is administered vaginally. The goal is to allow this medication to work and modify the conditions of the cervix, causing it to gradually efface and open, paving the way for the onset of labor.

Prostaglandins are substances derived from arachidonic acid that cause histological changes in connective tissue, similar to those seen at the beginning of labor in a full-term pregnancy (dissolution of collagen bundles and increased submucosal water content). These may be sufficient to initiate labor. Prostaglandin E1 analogs (misoprostol) and prostaglandin E2 analogs (dinoprostone) are used.

Labor induction:

The goal is to achieve contractions every 2-3 minutes, lasting 60-90 seconds. It can be performed after cervical ripening or initially if there is an indication of termination and a Bishop score of >6. How? By administering intravenous oxytocin or performing amniotomy (breaking the bag of waters).

References

1. Grobman WA, Rice MM, Reddy UM, Tita ATN, Silver RM, Mallett G, Hill K, Thom EA, El-Sayed YY, Perez-Delboy A, Rouse DJ, Saade GR, Boggess KA, Chauhan SP, Iams JD, Chien EK, Casey BM, Gibbs RS, Srinivas SK, Swamy GK, Simhan HN, Macones GA; Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal–Fetal Medicine Units Network. Labor Induction versus Expectant Management in Low-Risk Nulliparous Women. N Engl J Med. 2018 Aug 9;379(6):513–523. doi: 10.1056/NEJMoa1800566. PMID: 30089070; PMCID: PMC6186292.
2. WHO recommendations for induction of labor